The present invention relates to a roll for use in a printing operation and a method of making same and, more particularly, to a roll for removing undesirable foreign materials from the plates of a printing press and a method of making such roll.
The presence of undesirable foreign materials in printing operations causes defects in the printed product. Such foreign materials or particles are generally referred to in the trade as "hickies". If such hickies are not removed from the printing plates, they prevent the application of ink to all areas of the image resulting in small spots or defects. Hickies may, for example, include such foreign materials as dried ink specks, slitter dust, lint, paper specks, felt hairs and the like.
A number of different methods and apparatus have been employed in the past for removal of such hickies. Many of these apparatus involve the use of either natural or synthetic materials which are expensive or which may be difficult to clean.
In the United States Letters Patent No. 3,808,657 (MENGES et al), a roll is disclosed in which a flat calendered sheet of a rubber material is formed and in which nylon fibers are dispersed in the material. This calendered sheet is then wound upon a metal core and is vulcanized to the core. After vulcanization, the outer surface of the fiber filled covering is ground to produce a napped surface to form a hickey picker roll.
The hickey picker roll disclosed in the aforementioned Letters Patent and the method of making the roll suffer several disadvantages. One disadvantage is that the finished product has a seam which, in many instances, is undesirable. Another disadvantage is that the covering with the fibers therein is vulcanized directly to the heavy metal core. Accordingly, shipping expenses are substantially increased and refinishing of the rolls must be done at a facility which has the full mixing and vulcanizing capability as is required for the formation of the roll. Such facilities are not normally available in the field. Still another disadvantage of the aforementioned method is that separate sheet forming and winding steps are necessary which increases the cost of making the roll and necessitates additional equipment to perform these separate steps.
A principle purpose of the present invention is the formation of a roll which overcomes these several disadvantages and which roll is capable not only of picking hickeys, but what may also be used to carry water. The roll incorporating the principles of the present invention is preferably formed by extrusion of a covering containing the fibers dispersed therein onto a tubular mesh sleeve and the covering is vulcanized to the sleeve. Accordingly, the formed roll is seamless and the subassembly thereby formed need not include the heavy metal core. Thus, the vulcanized subassembly is lightweight and may easily be shipped to final processing facilities in the field where it may there be bonded to the heavier metal cores to the form the final roll. Shipping expenses are accordingly substantially reduced and turnaround time for the reprocessing of such rolls is also substantially reduced. Moreover, formation of the subassembly itself may take place at a fairly sophisticated central manufacturing facility where extensive and expensive test equipment, such as x-ray analysis apparatus may be present. Such equipment is not usually available in the field. It will also be seen that the roll and method of making the roll incorporating the principles of the present invention utilizes a one-step extrusion operation which eliminates the multiple sheet forming and winding steps of the prior art. The roll of the present invention may be formed of inexpensive, readily available materials and may be easily washed or otherwise cleaned in use by conventional materials and methods.
In one principle aspect, a roll incorporating the principles of the present invention for use in a printing operation includes a tubular mesh sleeve and a covering on the sleeve comprising an elastomer composition having a plurality of discrete fibers substantially uniformly dispersed therein, the covering being vulcanized to the sleeve.
In another principal aspect, the aforementioned roll includes a metal core and the tubular mesh sleeve is bonded to the core. A portion of the composition at the surface of the covering opposite the mesh sleeve is removed therefrom such that the ends of the fibers are anchored in the composition while opposite ends of the fibers are free to define a nap on the roll, and the nap is free of all matter which is not anchored to the composition.
In still another principal aspect of the present invention, a method of making a roll for use in a printing operation includes the steps of stretching a tubular mesh sleeve onto a metal mandrel, covering the sleeve with an elastomer composition having a plurality of discrete fibers substantially dispersed therein, vulcanizing the covering to the sleeve, and removing the mandrel.
These and other objects, features and advantages of the present invention will become clear upon a consideration of the following detailed description.